Model Number: EN-1015 Brand Name: ESUN/OEM/ODM Key Specifications/Special Features: 1. Auto-power off: in the absence of any operation, the calculator can help you keep the results in about a few minutes, after a few minutes, the calculator will automatically shut down to help you save power2. Battery/eco-friendly solar power supply: you can choose to use battery or solar energy, of course, the use of solar energy more environmentally friendly, as long as you begin to use a calculator, even without the battery, you can use right away, no longer have to worry about the calculator because there is no battery that can not be used3. Anodizing or satin-finished aluminum case: when you operate, hand touch feel better, operation more quickly and easily4. Point of humanized design: humanized design of the slope angle, it can be careful care of your health on vision and cervical spine